Imagine that you are riding a car in a very big road at a very fast speed, for example a comet, and suddenly you click the "F" button to leave the car. Niko falls out of the car , and bounces trough the road, he doesnt stop bouncing untill he hits a wall or something, i uploaded a vid(30seconds) showing this problem:

On the seconds 16 to 20 ( when i leave the car) you can notice that niko is actualy going ahead of the car, the car slows down and niko keeps bouncing on the road.
Now look at seconds 27 to 30 you can notice that niko stops a bit cuz of a step and suddenly starts going faster again.

I hope you understand what i mean. Why is this happening? im using mods like realism iv, 100 car pack, simple native trainer . I reinstalled it and tried it without mods and the same thing happens , it is from the game itself.

I play on laptop and i downloaded the trainer for laptops, this problem started right after i tested and installed the simple native trainer, i think its something associated with grabbing or force from the trainer, i think it is some option that does this,

I didnt install the normal simple native trainer becuz i can't get that one to work.
Gta 4 isnt much fun without the simple native trainer